Emil passburg



1%. 749,627. PATBNTBI) JAN. 12, 1904.

E1 PASSBURG. PROGESS 0F DRYING SUGAR LOAVES.

7 APPLICATION FILED PE BAB, 1908. F0 MODEL.

If! VENI'DI? WIN/E8353, (A

no. Maser.

Patented January 12, 1904.

FElQEt EMIL rasssuns, or BERLIN, GERMANY.

success or DRYlNG SUGAH-LQAVES.

SPECIFICATION forming part of Letters Patent No. 749,627, dated January 12, 1-904.

' Application and February 26,1903- Serial in. 146,276. (No man.)

To, alZ. whom it may concern:

Be it known that I, EMIL PASSBURG, engineer, a subject of the German Emperor, resid ing at No. 33 Bri'ickenalle, in the city of Berlin, Kingdom of Prussia, German Empire, have invented certain new and usefullmprovemerits in Processes of Drying Sugar-Loaves,

of which the following is a specification.

' The drying of sugar-loaves has been carried ing it off through drain-pipes, or vacuum drying apparatus are used for drying the loaves. The former process has the drawback that the drying not only takes a very long time, (about eight to twelve days,) but also that the sugarloaves lose to some extent the white color of their surface or mantle through this kind of evaporation and the prolonged efiiect of the the clariticr is concentrated into a smaller volheat, if the clarifying liquor used was not translucent and colorless, so that a yellowish tinge will show itself on the outside or in the mantle, which will make them poorloo king and of less value in comparison with the loaves dried in mm/.0. The cause of the formation of this yellowish tinge lies in the fact that through capillary attraction the moisture is drawn from the interior of the loaves to the surface and there dried up, for underatinospheric pressure the evaporation of the water of the sugardoaves can naturally only take place on the surface of the same. This moisture drawn by the capillary attraction to the surface of the sugar-loaves is a solution of sugar or syrup which has been used to give the loaves a white covering and which can never be completely driven out of the loaves, neither by clarifying nor by suction. It very frequently is still tinged slightly; but this slight tinge is not noticeable if the clarifier is distributed through the whole loaf equally. The tinge, however, shows itselfdistinctly if ume on the edge, the coating, or the mantle of the sugar-loaf. The long period of d rying contrlbutcs to increase th s \0ll )\\l$ll tinge, so

that in the interior of the loaves dried after this method, from which the clarifier has been drawn by capillary attraction, a white core will be seen, whereas the edge of the loaves where the clarifier has dried up, as shown in Figure 3 at f, shows a yellowish tinge.

WVith the vacuum-drying process, also the i one invented by me and protected by United States Patent No. 717,265, and more especially suited for fine-grained loaves, the yellowish tinge of the edge of the loaves, as well as the long drying period, and with it the prolonged action of the heat, are avoided, as through the formation of the vacuum the Water is con,- verted into steam in all parts of the previously- -heated loaves, also in the interior, and as steam it forces its way through the crystals of the loaves and is carried off by the air-pump. In this process the clarifying-syrup, which was at the beginning of the same evenly distributed in the loaves, crystallizes-that is to say, it becomes dry to a large extent in the course of a few hours through the evaporation of about eighty to ninety per cent. of the original percentage of water contained in the loaf, so that this solidified clari'fier can no longer be removed by capillary attraction;

but with the vacuum process in order to atstrongly-heated mantle of the loaves must be cooled again, so that the. heat will remain stored up in the still-damp interior of the loaves in order to bring about the evaporation of the remainder of the water bycreating again slowly and gradually a vacuum. This work of the subsequent heating, cooling, and

evacuation necessary in order-to remove a p1 aportionately small remainder of the weter--namely, ten to thirty per cent. of the original percentage--is by far the most tedious part of the whole process and requires about six to eight times more time than does the first evacuation-that is to say, thc'remoral of seventy to ninety per cent. of the crystallized. In

' remains damp.

' original and full amount of moisture.

the water amount of water of loaves heated outside of the vacuum drier.

Though the method of completing the drying process of the loaves in cacao be Without any doubt the most perfect drying method, because it not only considerably shortens the drying period in comparison with that of the stove-rooms, but also the sugar-loaves are given a uniformly white and beautiful appear ance, as the colored clarifier cannot, as above described, concentrate itself in this or that part of the loaf, but remains where it is in consequence ofthe rapid drying and becomes spite of these advantages the vacuum-drying process has the drawback that a greater outlay is needed to purchase the vacuum apparatus, and an exclusiveuse of the same has in some cases to .be abandoned for economical reasons. I

The hereinafter-described combination drying process has for its object to remove the drawback of expensiveness of the plant and yet to preserve as far as possible the advantages of the rapid vacuum drying over the inferior method and results of stove-room drying In the accompanying drawings, Fig. 1 represents a view, partly in elevation and partly in section, of a drying plant consisting of'a preliminary drier, vacuum drying apparatus, and final driers consecutively arranged for the successive steps of the drying operations. Fig. 2 shows a synoptic view of the drying plant; and Fig. 3 shows several views of the sugar-loaves as obtained by the vacuum, combined heating and vacu um, and heating processes, respectively.

Similar letters of reference indicate correspomlingparts.

This combination drying process consists in heating the warm sugar-loaves in a hot' room A, Fig. l, filled with air and then dry' ing themdn a vacuum apparatus B till the greater part of the water (about seventy to ninety per cent.) has evaporated, whereupon the loaves are put .into the final drier constructed after the system of the ordinary stove-rooms, so that in them the remainder of vaporates on the surface of the loaves. As in consequence of the extraction of the water in the vacuum apparatus B the greatest pa rt of the clarifying liquor becomes dry and hard, and therefore only a small part This smali quantity may be drawn by capillary attraction to the surface of the loaves in the final drier or dryingchamber (J and there be dried. in this way only-the edge of the sugar-loaf will show a slightly-darkish color, as the drying period in the final drier (I is of far less duration than with the ordinary process, where the loaves are taken into the stove-rooms with their There are, for instance, three warmingchambers A A A required, each of Which can hold that quantity of sugar-loaves which is to be placed into the vacuum apparatus B, as the period in which the loaves absorb the required evaporation heat in the warmers is about twelve hours, whereas the dr ing period in the vacuum apparatus amounts to only three to four hours, so that the vacuum apparatus B will receive, at intervals of about four hours. the loaves heated in the three warming chambers. After a preliminary drying in the vacuum apparatus B they get into the final heater C with drain-pipe S, where they dry and cool ninety-six hours. The final heaters must therefore be of a size suihciently large to hold eighteen times as much sugar as the vacuum apparatus, as the subsequent drying and cooling under atmospheric pressure occupies about eighteen times as much time as the preliminary dryingin the vacuum apparatus B. If instead of these final driers yacuum apparatus were used, there would be required to eight apparatus, whereas with this com: bination process one is sufiicient for drying the same quantity of sugar.

v The cost of constructing the final driers is very reduced, so that the cost of the whole plant required fol-this combination process considerably less than the cost of a number of vacuum apparatus, for which reason this process may claim to possess the advantage of great cheapncsscombined with com paretively very favorable results as regards the quality of the dried material.

3 shows a sugar-loaf (Z in sect-ion, dried Zn cacao, and consequentlyof a uniform whiteness in all its parts, whereas e represents a sugar-loaf treated by the combination drying process and showing, when compared with the loaf f, treated from beginning to end in the stove-rooms, a far less yellow-colored edge.

What I claim as my invention, and desire to secure by Letters Patent of the United States, is- I The process herein described of drying sugar: loaves, which consists in subjecting sugar-loaves to the action of a partial vacuum for partially extracting the moisture from the same, transferring said loaves into a nonvacunrn drying-chamber, and then subjecting the partially-dried loaves therein to a final heating action for extracting the remaining traces of moisture from the same, substantially as set forth.

In testimonythat I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

- EMIL PASSBURG.

Witnesses: v

WoLpEmAR HAUPT, IIENRY Hasrnn.

'in from forty-eight to llO 

